ocr: YESTERDAY The first ESA satellite to be placed in orbit was COS-B, launched in August 1975 I to study gamma-rays. COS-B was followed by GEOS (April 1977); ISEE (1977); EXOSAT and OTS-2, the Agency's first telecommunications satellite. ESA launched its first rocket, Ariane-1,in 1979. IUE, International Ultraviolet Explorer, was - joint venture between ESA, the United States and the United Kingdom. Launched into geosynchronous orbit in 1978, IUE was the longest lived astronomical satellite ever, working for over 18 years instead of the planned seven. IUE studied ultraviolet radiation and was spe ...
